Establishment of boundaries, limit setting and safety of patients and staff are important aspects of mental health care delivery, but some psychiatric patients appear unwilling to cooperate when faced with appropriate limits. They may become involved in violence, criminal damage or public order offences. Rates of assault by in-patients against staff are increasing (Schneiden, 1993). In NHS hospitals this has been found to range from 0.15 incidents per patient per year in rural settings to 0.60 incidents per patient per year in urban hospital settings (Drinkwater & Gudjonsson, 1989). A high rate has been confirmed recently among psychiatrists (Davies, 2001).